Grease interceptor



D 20, J. HIRSHSTEIN 2,140,581

GREASE INTERCEPTOR Filed Nov. 15, 1935 2 Sheets-Sheet l INVENTOR.

JOSEPH fiy/RsHs TEl/Y BY ATTORNEYS 20, 1938. HmsHsTEm 2,140,581

GREASE INTERCEPTOR Filed Nov. 15, 1955 2 Sheets-Sheet 2 ATTORNEYS nameI... 20,1938

umrans'rA'ri-zs PATENT OFFICE v 6mm smiths-mammoth Wu November 15. 19Serial No. 50,...

,IOW

This invention relates to an apparatus for reclaiming fatty wastematerials, oils and grease from waste waters and has particularapplication to the maintenance of a constant water level in suchapparatus so that. the accumulated fatty material may be collected andremoved by mechanical means.

In water clarifying apparatuses, or what are commonly known as oil orgrease interceptors, the basin in which the fatty material is allowed toaccumulate, should be sealed from the air. Building, Plumbing andsanitation codes specify this as a requirement. A water seal or trapmust also be provided, where the basin is connected to the sewer. Thus,in a grease interceptor construction whereingthe air above the level ofthe water in'the basin is. sealed from the atmosphere, many diflicultiesarise with respect to the operation of the interceptor and themaintenance of the water level therein.

The maintenance 'of a steady, constant water level in the interceptorbasin, is of primary importance. A quiescent steady level willhave theeffect -of' accumulating more grease and fatty material on the surfaceof the water than one which has a tendency to fluctuate. A fluctuatingwater level produces agitation in the quiescent zone of the interceptorand thereby much of the fatty material, which would otherwise be 30separated, remains in suspension in the water.

v A further advantage of maintaining a constant water level is foundwhere mechanical means are employed to skim off the fatty waste materialfrom the surface of the water. If the level is not maintained, it isobvious that mechanical means for removing the fatty waste material fromthe surface of the water become complicated. If

- the level is too low, only a portion of the grease will be removed,and in the alternative, if the 0 level is too high, grease and wastewater will'be removed together.

Having in mind the difliculties experienced in theoperation of greaseinterceptors, it is therefore the primary object of my invention tomainbasin of the interceptor, and particularly in the quiescent zonewhere the fatty and oil waste material collects. l

It is a further' object of my invention to provide a self-ventinginterceptor which can be used without a vent line and so that anaccumulation of trapped, compressed air and gases'above' the water levelcannot affect the operation of the clarifying apparatus.

/ Further and more specific objects of myinven tain a steady andconstant water level in the' tion will appear from the followingdescription given in connection with the accompanying drawings, whereFig. 1 is a centrally located vertical cross-section through aclarifying appa-, ratus, embodying my invention; Fig. 2 is a horimntalcross-section taken alongthe line 2-2 in Fig. 1; Fig. 3 is a fragmentaryhorizontal crosssection illustrating another form of my invention; Fig,4 is a centrally located vertical crosssection of the modification shownin Fig. 3; Fig. 5 is a vertical cross-section taken along the line ll inFig.4; and Fig. 6 is a-vertical section, similar to Fig. 5, showinganother form of my invention which is illustrated by the broken linesinterposed on Fig. 3.

As stated in one of the objects of my present invention, I propose theprovision of a grease and oil trap construction which can be usedwithout being equipped with a separate vent line, such as has been theexpensive practice heretofore. Should a grease trap of any one of theseveral types now in commercial use he installed without a vent line,and the trap be disposed a substantial distance below a dish washer orother source of greasy or oily water and no vent line be provided, asudden rush of the waste water into the trap would create a hydrostaticcondition and cause the gases and air between thetop level of the waterand grease in the trap and the cover thereof-to be compressed.

The compression of the water and gases within the top portion of thetrap, brings about a sudden and violent reaction in the nature of an airand a gas expansion which immediately causes an election of not only thewater present in the trap but also the fatty matters which it is desiredto retain in the trap, this ejection taking place through the outlet endof the trap. Thus, the very purpose and function of the trap isnegatived. The present invention contemplates an automatic self-ventingfeature in the trap construetion, so that when gas and air'pressureforms in the top of the trap for the reasons above stated, it willpermit automatic venting of the compressed gases directly to the outletof the trap, thus preventing the building up of a sumciently high gas orair-pressure to cause any appreciable fluctuation in the normal level ofthe water in the trap.

Referring now to Fig. 1, I have shown a clarifying apparatus having .8basin I, a waste water inlet 2, and a discharge opening 3. A verticaldischarge tube 4 communicates with the opening 3 and discharges into thedrain pipe 5, which is maintained at the same level as the inlet 2.

The basin I for accumulating the fatty waste material has side walls I0,end walls II, and a bottom l2. The bottom I2 is constructed so that itslopes from the inlet end to the discharge opening, and a centralchannel I3 is provided in the sloping bottom so that acceleration of thelower level of the waste water will be produced. A defleeting baflleplate I4 is secured to the side walls of the basin by means of lugs castintegrally .with the wall. The water thus entering the basin from theinlet 2 is deflected downwardly around the baiiie M, and agitation isproduced.

A second baiile plate I5 is disposed between the side walls It, so thatits upper extremity extends beyond the water level to be maintained.Thus a quiescent zone is established around the bailie plate I5 and theremaining portion of the basin I adjacent the outlet opening. A coverplate I6 completely encloses the space above the basin I and suitablepacking is provided around the edges of the cover plate. Fastening meansprovide a clamping pressure to maintain the cover plate in a sealedposition relative to the trap. When the waste water enters by the inlet2 it is diverted and distributed across the width of the basin by thebaflie I4. It is advisable to fill the basin. I with clear water to alevel such as indicated by the line A, to prevent greasy water 1 fromreaching the outlet. The level A will be maintained as soon as thestability of the device at the. discharge end has been overcome. The

level maintained in the basin II with respect to the discharge opening 5is commonly known to hydraulic engineers as the hydraulic grade line.Once this condition is established, the grease will always collect atthe same elevation in the quiescent zone before and behind the battleplate I5, so long as a constant water level is maintained.

If a large surge or hydraulic headis produced in. the inlet pipe 2, thewater level A will have the tendency to slightly rise. Along with thewaste water there will be a quantity of air carried by the water, as itenters the basin I. -The liberation of this air and a surge produced bya greater quantity of water flowing into the'basin I, will cause apressure to be exerted in the air space'B above the water level A.Unless this pressure is immediately relieved, the water level A willlower until all the water is exhausted from the basin by the combinedefiect of the pressure in the air space B, together with the syphonicaction produced by outward flow in the pipe 5. As water is anon-compressible liquid, this condition will repeat itself wheneversufficient pressure is produced in the space B above the liquid, line.Thus a surge produced by a great quantity of water entering the basinwill disrupt thequiescent state of the liquid line and a great amount ofthe fatty material collected on the surface thereof will be lost inthedischarge pipe.

To obviate this condition, I have provided means for relieving surebeyond normal in the space B above the water line. This is accomplishedwithout breaking the water seal effected by the trap 4. The air reliefdevice consists of a column or tube '20, vertically disposed within thebasin I. Its upper portion extends-well into the air space B, so that itis free from any accumulation of grease forming above the surface of thewater. The lower end of the column 2|) communicates with a similarvertical column of water 2| at the point 22 near the bottom of the basinI. The top portion of y accumulation of air presthe column 2| dischargesinto the opening 5 at substantially the waterlevel line through theopening 23. In the lower portion of the column 2| I have provided asmall opening 25, so that under normal conditions the columns 20 and 2|will remain filled with water and in balance, at substantially the waterlevel line A.

When a surge occurs in the inlet pipe 2, the pressure built up in theair space B will dissipate itself by lowering the level of the water inthe column 20. After the initial surge has passed,

. and the device again resumes normal conditions,

the level in the column 20 will again rise to the water level line A, byreason of the refilling hole 25. In the event that the surge is a greatone,

and the column 20 is not suflicientto balance the pressureproduced inthe air space B, then the water in the column 20 will recede downwardlyuntil the point 22 is reached. When this condition occurs,'the air willinfiltrate into the water and bubble up through the tube 2| and therebybe liberated out of the opening 23 and carried into the discharge pipe5. If the pressure in the space B be great enough, the water'in thepassageways 20 and 2| will be almost completely ejected. However, assoon as the surge is relieved the water seal between the discharge pipe5 and the basin I will be reestablished immediately through therefilling hole 25.

It has been found that the sensitivity with which the water level may bemaintained, is somewhat dependent upon the comparative sizes of thecolumns 20 and 2 I, and their internal characteristics as well as theirrelationship to the size of the basin. The time element is of importancein that the small quantity of water in the tube,2|| moves more rapidlyto relieve the pressure in the space B than does the greater quantity ofwater in the basin I, which is subject to the same pressure. This is dueto the fact that the pressure will be relieved at a place which offersthe least resistance to its escape. It is easier to momentarily move thesmall quantity in the tube 2|) than it is to overcome the inertia andmove the large body of water in the basin I, whenever a sudden surgeoccurs.

To accomplish my invention, any size tubing may be used in place of thecolumns 20 or 2|, as illustrated. These may be circular, oval or anyother shape that is convenient to cast. By increasing the size of thecolumn 2| with respect to the column 20, I find that the limits within.which the water level A will fluctuate, are greatly diminished. I If thecolumn 2|] were of greater size than the column 2|, a choking eifectwould occur in the leg 2 I, for the reason that the smaller column wouldoffer a restriction or throttle to the discharge of the water. Thus, bydiminishing the size of the column 20 with respect to the column 2 theformer is quickly emptied into the larger column and the air may thenbubble or escape up through the water remainingin the column, or, asstated, may eject the water from column 2|, but only under. flowingconditions. This principle is important as it is required under thepresent building, plumbing and sanitationcodes to maintain a trap orwater seal between the basin I and the discharge pipe 5.

I have shown in Fig. 2 the columns 20 and 2| as substantially oblongincross-section. As previously stated, this construction isnot the onlyform which will accomplish my invention. The columns may be of variousshape or the smaller column 20 may be disposed within the larger .column2|, in which case the air would tube 20 and upwardly through the outercolumn 2!... 'This latter construction is shown in Figs. 3,

,4 and 5 as another form of my invention.

The column 20a in Figs. 3, 4 and 5 is centrally located within thecolumn 2|, and the refilling hole a is correspondingly placed, asillustrated with reference to Fig; 1. To avoid any obstruction of thepassageway. by the upward extension of the tube 20a, I have shown asanother form of my invention in Figs. 3 and 6, the tubes 20b disposed,either singularly or in plurality, at the corners of the column 2|.Openings 25b are similarly placed in 'each tube in order to refill thetubes, as previously described. g

It may thus be seen that I have invented a new and useful improvement ingrease interceptors, whereby the water level may be retained withsuflicient' accuracy so that mechanical means may be employed forremoving the grease therefrom. It is also apparent that the maintenanceof the water level increases the efliciency of operation of theinterceptor and the romoval of fatty waste material from the wastewaters.

I claim:

1. In a clarifying apparatus for waste water, an enclosed basin havingan inlet and having an outlet arranged to maintain a normal water levelin the basin below the top thereof, conduit means for containing acolumn of water opening into the outlet and extending substantiallybelow the .water level in the basin, a second conduit meanscommunicating with the lower extremity of the first named means, andextending upwardly into and communicating with the space above the waterin the basin.

2. In a clarifying apparatus for waste water,

wardly into and communicating with the space above the water in thebasin, and an opening in said second 'conduit means disposed below thelevel of the water so that the column may be reillled and maintained atthe same level as the water in the basin. I

3. A device for separating waste material from waste water, comprisingan enclosed basin having an inlet and having an outlet arranged tomaintain a normal .water level in the basin below the top thereof,conduit means for containing a column of water opening into the outletat the normal water level and extending below the surface thereof, asecond conduit means of lesser cross-section than said first-named meanscommunicating with the lower extremity of said first named ,means andextending into the space above thelevel of .the water in the basin, andan opening in said last-named means located below the surface of thewater, so that the level of the water in the columns will normally bethe same as the the outlet and extending below the surface of the waterin the basin, a second conduit means disthereof, conduit means forcontaining a column posed within the first-named means and communicatingwith the same at its lower extremity, said second means extendingupwardly into the space above the water level in the basin.

5..In a device for separating fatty material from waste waters, anenclosed basin having an inlet and an outlet arranged to maintain anormal water level in the basin below the top thereof, conduit means forcontaining a column of water opening into the outlet and extending belowthe surface of the water in the basin, and a plurality of other conduitmeans communicating with the lower extremity of the first-named meansand extending upwardly into the space above the surface of the. water inthe basin.

6. In a device for collecting fatty waste material from water, anenclosed basin having an inlet and having an outlet arranged to maintaina normal water level in the basin below the top thereof, conduit meansfor containing a column of water opening into the outlet at the level ofthe water in the basin, a plurality of other condu lt meanscommunicating with the lower extremity of the flrst-named'means andextending upwardly into the space above the level of the water in thebasin, and a small opening disposed in each of said last-namedmeans,substantially below the level of the water, so that the columns mayberefilled and maintained at the same level as the water in the basin.

7. In a device for separating fatty material from waste waters, anenclosed basin having an inlet and having an outlet arranged to maintaina normal water level in the basin below the top of water opening intothe outlet at substantially the level of the water in the basin andextending below the surface thereof. a plurality of other conduit meanshaving a cross-sectional area of less than that of the first-named meansand communicating with the lower extremity of said first-named means,and extending upwardly into the space above the surface of the water inthe basin, and an opening in each of said last-named means, locatedbelow the surface of the water in the basin and communicating therewithso that the columns will maintain the same level as the water in thebasin.

8. In an apparatus for separating fatty waste material from water, anenclosed basin having an inlet and having an outlet arranged to maintaina normal water level in the basin below the top thereof, conduit meansfor containing a column of water opening into the outlet andextending'substantially below the level of the water in the basin, aplurality of other conduit means disposed within the firstnamed meansand com municating with the same near its lower extremity, saidlast-named means, each extending upwardly into the space above thesurface of the water in the basin.

9. In an apparatus for separating fatty waste material from waste water,an enclosed basin having an inlet and having an outlet arranged tomaintain a normal water level below the top thereof, conduit means forcontaining a column of water opening into the outlet and extending belowthe surface of the water in the basin, a plurality of other conduitmeans disposed within the first-named means and communicating with thesame at its lowerextremity, said last-named means each extendingupwardly into the space above the water level, and a small opening ineach of said last-named means disposed below the level of the water inthe basin so that the I form a water seal for the basin, and meanscommunicating with the outlet for relieving an accumulation of gases inthe space above the level of the water in the basin without breaking thewater seal or permitting the return of gases from 5 the outlet to thebasin.

JOSEPH

